Trim decimals

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 ## 2.7.1 under development
 
-- no changes in this release.
+- New #156: Add `NumericHelper::trimDecimalZeros()` (@samdark)
 
 ## 2.7.0 November 23, 2025
 

src/NumericHelper.php

@@ -122,7 +122,7 @@
     }
 
     /**
-     * Converts human readable size to bytes.
+     * Converts human-readable size to bytes.
      *
      * @param string $string Human readable size. Examples: `1024`, `1kB`, `1.5M`, `1GiB`. Full
      * list of supported postfixes in {@see FILESYSTEM_SIZE_POSTFIXES}.
@@ -157,9 +157,36 @@
                 throw new InvalidArgumentException("Not supported postfix '$postfix' in input string: $string");
             }
 
             return (int) ((float) $numericPart * $postfixMultiplier);
         }
 
         throw new InvalidArgumentException("Incorrect input string: $string");
     }
+
+    /**
+     * Trims trailing decimal zeros from a numeric-like string.
+     *
+     * If the fractional part consists only of zeros, the decimal separator is removed as well.
+     * The value that is `null` or empty is returned as-is.
+     *
+     * @param string|null $value String representation of a number or any string potentially
+     * containing a decimal part.
+     *
+     * @return string|null The input string with trailing decimal zeros (and a trailing decimal
+     * separator, if any) removed, or `null` if the input was `null`.
+     */
+    public static function trimDecimalZeros(?string $value): ?string
+    {
+        if ($value === null || !str_contains($value, '.')) {
+            return $value;
+        }
+        /** @psalm-suppress PossiblyNullArgument */
+        $value = rtrim($value, '0');
+
+        if ($value === '' || !str_ends_with($value, '.')) {
+            return $value;
+        }
+
+        return substr($value, 0, -1);
+    }
 }

tests/NumericHelperTest.php

@@ -170,4 +170,28 @@ public function testConvertHumanReadableSizeToBytesWithInvalidStrings(string $st
         $this->expectExceptionObject(new \InvalidArgumentException($message));
         NumericHelper::convertHumanReadableSizeToBytes($string);
     }
+
+    public static function decimalZerosProvider(): array
+    {
+        return [
+            'no decimals in integer with zeros' => ['390', '390'],
+            'all zeros' => ['390.000', '390'],
+            'no zeros' => ['3.14', '3.14'],
+            'some zeros' => ['42.010', '42.01'],
+            'null' => [null, null],
+            'zeros' => ['0.0', '0'],
+            'empty' => ['', ''],
+            'decimal only' => ['.5', '.5'],
+            'start with zero' => ['0.25', '0.25'],
+            'negative' => ['-3.000', '-3'],
+        ];
+    }
+
+    /**
+     * @dataProvider decimalZerosProvider
+     */
+    public function testTrimDecimalZeros(?string $input, ?string $expected): void
+    {
+        $this->assertSame($expected, NumericHelper::trimDecimalZeros($input));
+    }
 }